Effect of salinity, temperature and storage time on mouse experimental infection by Cryptosporidium parvum

Freire-Santos, F; Oteiza-López, A.M; Vergara-Castiblanco, Claudia; Ares-Mazás, Elvira

doi:10.1016/s0304-4017(99)00160-0

Cited by 30 publications

(17 citation statements)

References 15 publications

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“…Although the presence of infective forms of piscine cryptosporidia in live food of fish has not been investigated, the present results suggest that Artemia may act as a vehicle of infection for this parasitic disease. Although in vitro assays do not necessarily predict what will occur in vivo assays, it is demonstrated that the technique of inclusion/exclusion of fluorogenic vital dyes used in this study is consistent with the results obtained in a neonatal murine model used to evaluate the viability and infectivity of C. parvum oocysts (Freire-Santos et al 1999.…”

Section: Resultssupporting

confidence: 77%

Possible involvement of Artemia as live diet in the transmission of cryptosporidiosis in cultured fish

2007

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The viability of Cryptosporidium parvum oocysts ingested by Artemia franciscana metanauplii was evaluated using two fluorogenic vital dyes. There was no significant difference (p = 0.09) between the viability of oocysts maintained in saline (control) and those recovered from the digestive tract of the microcrustacean 24 h after ingestion (95 vs 90% viable oocysts). The results suggest that Artemia, used as a life food in fish larviculture, may act as a vehicle for transmission of piscine cryptosporidiosis caused by Cryptosporidium molnari and Cryptosporidium scophthalmi.

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Section: Resultssupporting

confidence: 77%

Possible involvement of Artemia as live diet in the transmission of cryptosporidiosis in cultured fish

2007

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“…While water-borne Cryptosporidium oocysts appear to be resilient at a wide range of temperatures (3,6,10,11,21,45), increased holding temperatures correspond to decreased oocyst infectivity (6). The ability of Cryptosporidium oocysts to initiate infection has been linked to finite carbohydrate energy reserves in the form of amylopectin, which are consumed in direct response to ambient environmental temperatures (6).…”

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confidence: 99%

Environmental Temperature Controls Cryptosporidium Oocyst Metabolic Rate and Associated Retention of Infectivity

King

Keegan

Monis

et al. 2005

Appl Environ Microbiol

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Cryptosporidium is a significant cause of water-borne enteric disease throughout the world and represents a challenge to the water industry and a threat to public health. In this study we report the use of a cell culture-TaqMan PCR assay to measure oocyst inactivation rates in reagent-grade and environmental waters over a range of temperatures. While oocysts incubated at 4°C and 15°C remained infective over the 12-week holding period, we observed a 4 log 10 reduction in infectivity for both 20 and 25°C incubation treatments at 12 and 8 weeks, respectively, for all water types examined, a faster rate of inactivation for oocysts than previously reported. This temperature-dependent inactivation was further investigated using a simple and rapid ATP assay described herein. Time course experiments performed in reagent-grade water at incubation temperatures of 4, 15, 20, 25, 30, and 37°C identified a close relationship between oocyst infectivity and oocyst ATP content, demonstrating that temperature inactivation at higher temperatures is a function of increased oocyst metabolic activity. While water quality did not affect oocyst inactivation, biological antagonism appears to be a key factor affecting oocyst removal from environmental waters. Both the cell culture-TaqMan PCR assay and the ATP assay provide a sensitive and quantitative method for the determination of environmental oocyst inactivation, providing an alternative to the more costly and time-consuming mouse infection assay. The findings presented here relating temperature to oocyst inactivation provide valuable information for determining the relative risks associated with Cryptosporidium oocysts in water.

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“…However, the significance of oocyst numbers is questionable, since storage duration and environmental conditions, such as pH, temperature, and/or the presence of oxidants, are likely to influence oocyst viability (5, 10, 18). Moreover, factors such as salinity, temperature, or storage duration may not decrease the infectivity enough to prevent infection in susceptible individuals (11,12).Oocyst viability is currently estimated by the quantitation of in vitro excystation rates or by incorporation of nucleic acid dyes (7). However, dyeing is influenced by the degree of oocyst permeabilization and may not reflect parasite infectivity (3,21).…”

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confidence: 99%

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confidence: 99%

Quantitative Flow Cytometric Evaluation of Maximal Cryptosporidium parvum Oocyst Infectivity in a Neonate Mouse Model

Delaunay

Gargala

Li³

et al. 2000

Appl Environ Microbiol

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The importance of waterborne transmission of Cryptosporidium parvum to humans has been highlighted by recent outbreaks of cryptosporidiosis. The first step in a survey of contaminated water currently consists of counting C. parvum oocysts. Data suggest that an accurate risk evaluation should include a determination of viability and infectivity of counted oocysts in water. In this study, oocyst infectivity was addressed by using a suckling mouse model. Four-day-old NMRI (Naval Medical Research Institute) mice were inoculated per os with 1 to 1,000 oocysts in saline. Seven days later, the number of oocysts present in the entire small intestine was counted by flow cytometry using a fluorescent, oocyst-specific monoclonal antibody. The number of intestinal oocysts was directly related to the number of inoculated oocysts. For each dose group, infectivity of oocysts, expressed as the percentage of infected animals, was 100% for challenge doses between 25 and 1,000 oocysts and about 70% for doses ranging from 1 to 10 oocysts/animal. Immunofluorescent flow cytometry was useful in enhancing the detection sensitivity in the highly susceptible NMRI suckling mouse model and so was determined to be suitable for the evaluation of maximal infectivity risk.Cryptosporidium parvum is presently identified as a common cause of diarrhea in immunocompetent individuals. In immunodeficient individuals, cryptosporidiosis may lead to lifethreatening chronic diarrhea, and, because of the incidence of AIDS, the disease poses a significant public health problem in developing countries where AIDS is endemic (8,14,17,22).Recent outbreaks of cryptosporidiosis support the concern about C. parvum oocyst contamination of treated and surface water (15). In Sydney, Australia, from July to September 1998, contamination of the drinking water supply involved over 3,000,000 residents (16).Water oocyst count is a commonly used parameter to evaluate the infectious risk. However, the significance of oocyst numbers is questionable, since storage duration and environmental conditions, such as pH, temperature, and/or the presence of oxidants, are likely to influence oocyst viability (5, 10, 18). Moreover, factors such as salinity, temperature, or storage duration may not decrease the infectivity enough to prevent infection in susceptible individuals (11,12).Oocyst viability is currently estimated by the quantitation of in vitro excystation rates or by incorporation of nucleic acid dyes (7). However, dyeing is influenced by the degree of oocyst permeabilization and may not reflect parasite infectivity (3,21). Oocyst infectivity can be evaluated by monitoring in vitro parasite development in highly permissive cells (9,13,24). In vivo, C. parvum infection is usually investigated using susceptible animal models such as immunocompromised or neonatal mice (19).The aim of this work was to assess C. parvum oocyst infectivity using a suckling mouse model (6). Flow cytometry, a rapid and simple alternative to microscopy, was used to detect viable oocysts and to docume...

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Effect of salinity, temperature and storage time on mouse experimental infection by Cryptosporidium parvum

Cited by 30 publications

References 15 publications

Possible involvement of Artemia as live diet in the transmission of cryptosporidiosis in cultured fish

Possible involvement of Artemia as live diet in the transmission of cryptosporidiosis in cultured fish

Environmental Temperature Controls Cryptosporidium Oocyst Metabolic Rate and Associated Retention of Infectivity

Quantitative Flow Cytometric Evaluation of Maximal Cryptosporidium parvum Oocyst Infectivity in a Neonate Mouse Model

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